Ultraviolet (UV) photodetectors (PDs) have been widely used in commercial, scientific and military fields, such as pollution monitoring, water purification, short-range communication security, NASA aerospace applications, information storage technology, flame sensing and early missile plume detection. ZnO is an excellent semiconductor material for UV detection due to its wide bandgap, excellent thermal and chemical stability as well as electrical, mechanical, and optical properties. To improve field of view and illumination uniformity as well as aberrations compared to planar UV PDs, the stretchable approaches were used in carrying out UV PD arrays on hemispherical surfaces of cameras with the mammalian eye geometrical layouts, thereby offering important advantages for applications in the astronomical observation, missile defense and satellite technology, as examples.
Stretchable electronics hold a promising future for next-generation applications beyond the extents of traditional semiconductor wafers and circuit board technologies, benefiting from their unique capacity to integrate with soft materials and curvilinear surfaces, and thus allow us to use in biomedical sensors, wearable devices and robotic skins. Over the past few years, a wide variety of deformable devices were presented sequentially by using various soft materials (such as ultrathin silicon wafers (thickness range: from 2 to 10 μm), Polydimethylsiloxane (PDMS) substrates and 2D materials) and particular structures (such as island bridges, open mesh geometrics and wavy shapes), respectively. However, most of above-mentioned strategies of making stretchable electronics are complex and costly.
Paper, a soft material with truly low cost (one tenth the price of plastic film, one percent as much as silicon), has a lot going for it—lightweight, flexible, biodegradable and recyclable. Via proper additives and manufacturing processes, paper can emerge a seemingly endless range of properties (such as hydrophilic or hydrophobic, porous or watertight, opaque or nearly transparent, delicate or strong, coarse or about as smooth as glass). Up to date, a lot of reports have discussed paper-based electronics, such as TFTs, solar cells, LEDs, RFID tags, electronic memory devices and light sensors, proposing low-cost fabrication processes (e.g., spin coating, inkjet printing and sputtering). However, as compared to soft materials (such as ultrathin silicon wafers (the strain of ˜1%), PDMS substrates (the strain of ˜100%) and 2D materials (the strain of <10%)) and electronics with particular structures (such as island bridge (the strain of 20 to ˜150%), open mesh geometrics (the strain of 18%) and wavy shape (the strain of ˜5%)20), the stretchability of electronics based paper is still low (less than 1%), thus hindering practical applications.
There remains a need for improved optoelectronic devices such as photodetectors that are durable and inexpensive to make.
It is therefore an object of this disclosure to provide improved optoelectronic devices that can be made inexpensively and can be durable under a variety of conditions.
It is also an object of this disclosure to provide inexpensive methods of making improved optoelectronic devices.
It is an additional object of this disclosure to provide methods of using the improved optoelectronic devices, for example in detecting ultraviolet radiation.